1. Field of the Invention
The present invention relates to a toner for electrostatic image development used for developing electrostatic latent images formed in electrophotography, electrostatic recording method, electrostatic printing, and the like.
2. Discussion of the Related Art
A polyester is inherently excellent in the fixing ability. For the purpose of further improving the fixing ability, there have been made various studies on resin binders for toners comprising a polyester obtainable from an alcohol component consisting essentially of an aliphatic alcohol.
For instance, Japanese Patent Laid-Open Nos. Hei 1-204065, Hei 2-161467, and Hei 10-268558 each discloses a toner comprising as a resin binder a polyester obtained by polycondensing a monomer mixture comprising an aromatic dicarboxylic acid, an aliphatic diol, and a trivalent or higher polyvalent monomer. However, these toners are liable to cause filming even though their fixing ability is excellent.
Various reports have been made on toners with improvement of the defects of each resin by using a mixture of resins having different softening points as a resin binder, among which a combination of polyesters each made from an aromatic alcohol has been most numerously studied (Japanese Patent Laid-Open Nos. Hei 4-362956, Hei 4-313760, Hei 8-320593 and the like). In addition, Japanese Patent Laid-Open Nos. Hei 11-305486 and Hei 12-39738 each discloses a toner comprising a polyester made from an aliphatic alcohol and a polyester made from an aromatic alcohol as resin binders. However, none of these toners disclosed in the publications have sufficient improvements in pulverizability, fixing ability and filming resistance. Therefore, further improvements in these properties have been desired in a toner for high-speed devices.
An object of the present invention is to provide a toner for electrostatic image development which has excellent pulverizability and fixing ability, and hardly causes filming.
These and other objects of the present invention will be apparent from the following description.